This invention relates to an image forming apparatus that prints an image onto a recording medium.
In a conventional image forming apparatus, the following comparison is performed in order to control stains, such as a rubbing stain and a transfer stain, on a recording medium at duplex printing. That is, since these stains are caused by a sheet feed roller pressed against the recording medium, an amount of print data to be printed on a contact zone of the front face of the recording medium against which the sheet feed roller is pressed is compared with an amount of print data to be printed on a contact zone of the back face against which the sheet feed roller is pressed. Printing is firstly started to the face having less print data.